Studies in Universal Logic Daniel Parrochia Pierre Neuville Towards a General Theory of Classifi cations StudiesinUniversalLogic SeriesEditor Jean-Yves Béziau (Federal University of Rio de Janeiro and Brazilian Research Council,RiodeJaneiro,Brazil) EditorialBoardMembers HajnalAndréka(HungarianAcademyofSciences,Budapest,Hungary) MarkBurgin(UniversityofCalifornia,LosAngeles,USA) Ra˘zvanDiaconescu(RomanianAcademy,Bucharest,Romania) JosepMariaFont(UniversityofBarcelona,Barcelona,Spain) AndreasHerzig(CentreNationaldelaRechercheScientifique,Toulouse,France) ArnoldKoslow(CityUniversityofNewYork,NewYork,USA) Jui-LinLee(NationalFormosaUniversity,HuweiTownship,Taiwan) LarissaMaksimova(RussianAcademyofSciences,Novosibirsk,Russia) GrzegorzMalinowski(UniversityofŁódz´,Łódz´,Poland) DarkoSarenac(ColoradoStateUniversity,FortCollins,USA) PeterSchröder-Heister(UniversityTübingen,Tübingen,Germany) VladimirVasyukov(RussianAcademyofSciences,Moscow,Russia) Thisseriesisdevotedtotheuniversalapproachtologicandthedevelopmentofa generaltheoryoflogics.Itcoverstopicssuchasglobalset-upsforfundamental theoremsoflogicandframeworksforthestudyoflogics,inparticularlogical matrices,Kripkestructures,combinationoflogics,categoricallogic,abstractproof theory,consequenceoperators,andalgebraiclogic.Itincludesalsobookswith historicalandphilosophicaldiscussionsaboutthenatureandscopeoflogic.Three typesofbookswillappearintheseries:graduatetextbooks,researchmonographs, andvolumeswithcontributedpapers. Daniel Parrochia (cid:2) Pierre Neuville Towards a General Theory of Classifications DanielParrochia PierreNeuville DepartmentofPhilosophy EcoleNationaleSupérieuredesSciences UniversitéJeanMoulin–LyonIII del’InformationetdelaBibliothèque Lyon,France Villeurbanne,France ISBN978-3-0348-0608-4 ISBN978-3-0348-0609-1(eBook) DOI10.1007/978-3-0348-0609-1 SpringerBaselHeidelbergNewYorkDordrechtLondon LibraryofCongressControlNumber:2013936647 MathematicsSubjectClassification(2010): 03-XX,03Axx,06-XX,62H30,91C20 ©SpringerBasel2013 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation, broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology nowknownorhereafterdeveloped.Exemptedfromthislegalreservationarebriefexcerptsinconnection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. 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Printedonacid-freepaper SpringerBaselispartofSpringerScience+BusinessMedia(www.birkhauser-science.com) “Formal logicisnothingbutthestudyofthe propertiescommontoallclassifications;it teachesusthattwosoldierswhoaremembers ofthesameregimentbelongbythisvery fact tothesamebrigade,and consequentlytothe samedivision;andthewholetheoryofthe syllogismisreducedtothis.Whatis,then,the conditionnecessary fortherulesofthislogic tobevalid?Itisthattheclassificationwhich isadoptedbeimmutable.Welearnthattwo soldiersare membersofthesameregiment, and wewanttoconcludethattheyare membersofthesamebrigade;wehavethe righttodothisprovided thatduring thetime spent carryingonourreasoning oneofthe twomenhasnotbeentransferred fromone regimenttoanother”. HenriPoincaré(LastEssays) “Onemorningatdawn,hemadehiscry heard, whichistosay, asort ofchirping, or more ofameowing,ormoreofabarking, or more ofalowing,well,that’salmostit,a roar, ormore exactlyatrumpeting,yes,that’s theword, asort ofchirping.” EricChevillard(Palafox) “Thentheclientcamein,toldhimthathe wantedtowrite;so, thepublicwritertook fromhisboxapackofallfixedletters,chose therightoneand copieditdownonthe paper... Because, infact,allthatmencan telloneanother,fromcasetocase—the youngmantohisfiancée,thefathertohis son,thetradertohiscustomer—wastobe codifiedunderfiveorsixdifferentpatterns, wherethere wasnothingtochange, apart fromthenameandthenumbers.” PandelisPrevelakis(ChronicleofaCity) “InChina,apopularnameforthegiant pandais“large bearcat”(Chinese大熊猫, pinyindàxióngma¯o),fromdà(大) large, xióng(熊)bearandma¯o (猫)cat,which suggests, according totheplaceofthe adjectivesinChinese,thatpandaswouldbe cats.Indeed,DNAanalysisshowsthatthe pandasshare withthebears90percent of theirgeneticinheritance,andthatthestaying 10percent,ofcourse, doesnotcomefrom cats.” AChinesestudent(Privateconversation) Preface This book is an essay in epistemology of classifications, not a mathematical text- book or monograph. Except in a few pages, we do not present results of our own. Whenitisthecase,wemustrecognizetheyareoftenelementaryones.Indeed,our main purpose is not to provide an exposition of an actual mathematical theory of classifications, that is, a general theory which would be available to any kind of them:hierarchicalornothierarchical,ordinaryorfuzzy,overlappingornotoverlap- ping,finiteorinfinite,andsoon,foundingallpossibledivisionsoftherealworld. Forthemoment,suchatheoryisbutadream.Weareessentiallylistingquestions. Our aim is, in fact, to expose the “state of the art” of this moving field and the philosophy one may eventually adopt to go further. To say a little more, we shall speakofsomeadvancesmadeinthelastcentury,discussafewtrickyproblemsthat remaintobesolved,and,aboveall,showtheverywaysopenforthosewhodonot wishtostayanylongeronthewrongtrack. Letusbrieflyexplaintheimportanceofthesubject. ALongHistory Finite classifications, as an economical way of grouping objects to simplify our understanding of the world (one may start with this “intuitive” definition), have been known since Antiquity and may already be found in the writings of Plato or Aristotle(see[371,376,377,383]).1 1Ofcourse,theviewsofPlatoandAristotleaboutclassificationsareverydifferent.Allalongthe Dialogues,andespeciallyinthelatestones(Parmenides,Sophist,Politicus,Philaebus...),Plato obviouslyusedtoclassalotofthings(WaysofLife,PoliticalConstitutions,Pleasures,Arts,Jobs, KindsofKnowledge,etc.),generallyinrelationwiththe“distance”thatseparatesthemfromtheir archetypalforms—whichgivessomeorder(orpreorder)onthem.But,asAristotleargues,itis quiteimpossibletoexplainwhatexactlythisparticipationorimitationis.Thepropertiesthatthe formshave(eternal,unchanging,transcendent,etc.)arenotcompatiblewithmaterialobjectsand themetaphorofparticipationorimitationbreaksdowninanumberofcases.Forinstance,what vii viii Preface Though scholastic thought put these classifications to good use, taxonomy as a fully fledged discipline actually began to develop with the birth of natural science intheClassicalAge,andwiththeneedtoorganizeflorasandfaunasinconnection with the growth of human population on earth, in the context of the beginning of agronomy (see [115, 117]). A century later, following the progress of technology, Chemistryitselfbegantobeascience.ComingaftertheworksofLavoisierandAu- gusteLaurent,andalotof,oftenunsuccessful,essays,Mendeleev’sPeriodicTable of the Elements were given all the credit for winning the victory. Since that time, all sciences have made use of classifications (especially physics, where important fieldsneedtobeorganizedbynon-trivialmathematicalstructures:forinstance,dis- cretegroupsincrystallography,orLiegroupsinquantummechanicsandelementary particlephysics). ProgressinLibraryClassifications At the end of the XIXth century, the development of scientific research, which raised the question of information storage and retrieval, encouraged the constitu- tionofvoluminouslibrarycatalogs:e.g.,Dewey’sdecimalclassification,Otletand La Fontaine’s universal decimal classification (see [138]), Herbert Putnam’s Li- braryofCongressclassification(see[426]).InthecourseoftheXXthcentury,new modes of indexing and original classification schedules appeared in this domain withS.R.Ranganathan(see[411,412])andhisfacetedclassification,while,inthe middleofthe1950s,aClassificationResearchGroupwasconstitutedandmanyin- ternationalconferencesonscientificinformationorganized(London1946,Chicago 1950,Dorking1957,Washington1958,Cleveland1959,Elsinore1965...). Sincethattime,somerareattemptstodevelopaformalizedapproachtoclassi- fications were made by authors like R.A. Fairthorne, C.N. Mooers, B.C. Vickery (see[489,490])orJ.Farradane(see[161,162]),theverystartofamathematicsof classifications having already existed since the end of the 1940s, as mentioned in a brief paper of the Journal of Symbolic Logic (see [89]) where Alonzo Church’s review studied the work of R.A. Fairthorne, including discussions of A.B. Agard Evans,T.H.O’BeirneandE.M.R.Ditmas.2 Infact,thoseresearchesneverreached thelevelofageneraltheory. doesitmeanexactlythatawhiteobjectbesaidtoparticipateinorcopytheformofwhiteness? Mustwethinkthattheformofwhitenessiswhiteitself?Howcouldtherebewhitenesswithout anythingwhichwouldbewhite?Whatcanawhiteobjectandtheformofwhitenessbesaidto haveincommon?AccordingtoAristotle([9],I,9),theformsfailtoexplainhowtherecouldbe permanenceandorderintheworld.Farmore,intheviewoftheStagyrite,theycannotexplain anythingatallinourmaterialworld. 2Inthisperiod,thatfollowedthesecondworldwar,thegrowthofinformationbegantonecessitate coordination (see, for instance, [130] and [131]). A decade later, information science was still lookingforalanguage(see[350]),andaneffectivepractice(see[163]). Preface ix InEurope,especiallywithintheappliedfieldsoflibrary,lifesciencesandsocial studies,anumberofpapersonclassificationresearchwerepublishedduringthenext twentyyearsinInternationalClassification,theGermanjournalfoundedin1973by DrIngetrautDahlberg.3 Atthesametime,researchmadeprogressinFrancewithscholarslikedeGrolier ([211])whopublishedsomemasterpapersinafamousFrenchlibraryreview(see [212])orZ.Dobrowolski(see[132]),agreattaxonomistinthefieldoftechnology. However,mostofthesepaperswerenotactuallyconcernedwithamathematics of classifications and, around the 1990s, the interest in classifications themselves tendsapparentlytodecline,thetitleofDahlberg’sjournalsoonbeingchangedinto Knowledge Organization, a much more general and up-to-date topic. The subse- quentarrivalofthedesktopcomputer,followedbythegrowthofnetworksprovid- ingaccesstoanalmostincrediblequantityandvarietyofresources,stillkeptaway from a purely algebraic approach to the problem, automatic clustering and analy- sis of data being essentially reduced—especially in France—to multidimensional appliedstatistics(see[36–38,83,257]). Curiously, until recently, library scientists were not necessarily very aware of these mathematical developments in classification science (see [386]). Some time ago,mostofthem,indeed,continuedtoworkwithtraditionalformsoflibraryclas- sifications.Forexample,inhisVocabulaireélémentairedesclassifications,theBel- gianlibrarianAndréCanonnestillspeaksoftheCDUofOtletandLaFontaine(or their followers), and of the Bibliographic Classification of Bliss, as good classifi- cations(Bliss’sone,thoughnotperfect,beingforhim,undertheformofBC2(the newBlissclassification),the“bestintheworld”,atleastatthetime(see[76],19)). He was even considering that such classifications, thanks to their analytical divi- sions, anticipate in fact some aspects of Ranganathan’s faceted classification.4 On the other side, those who were concerned with advanced studies in classification theory tried essentially to convince professionals that it is possible to improve the Colon Classification of Ranganathan (see, for instance, [226, 346]), which tries to gobeyondenumerativeorsemi-enumerativeclassificationschemesalreadyinuse,5 3Forabriefhistoryofclassifications,fromtheviewpointoflibrarysciences,seethepapersofthis author,forinstance[118]or[119].Forrecenttransformationsofthelibrarydomain,seeParrochia [382,385]. 4Letusgiveasimpleexample:intheUDC,insteadofforeseeing,inthesameclass,indexesdenot- ingpermanentorrecurrentconcepts—forinstance,the“gothic”intheFine-Artsclass(7)—,one mayapply,exceptincertaincircumstances,theanalyticaldivision033.5forindicating“gothic”, aconceptwhichnever appears,asamatteroffact,inprimitiveorderivedclasses.Soonewill neverfind“gothicarchitecture”nor“gothicchurches”intheArchitectureclass(72),butonewill beallowedtoconstructthosesymbolsbyaddingtotheindexestheappropriateanalyticaldivision: 72.033.5,“gothicarchitecture”;726.6.033.5:“gothicchurches”(see[76],70). 5DeweyDecimalClassification(DDC)orLibraryofCongressClassification(LCC)areenumer- ative systems which start with a list of possible subjects, each with a corresponding number, whosedivisions areoftenarrangedin a hierarchicmanner, frommost generaltomost specific. In those systems, each document (book, paper, webpage, etc.) to be cataloged is then assigned oneofthenumbersinthescheme.Bliss’sclassification,becauseofthepossiblecombinationsof